Safety type fuse assembly



May 17, 1938. E. R. MILLIS SAFETY TYPE FUSE ASSEMBLY Original Filed June 27, 1936 INVENIOR. 7 15.8 M////.'::

@ATTORNEY.

Registered May 17, 1938 UNITED STATES PATENT OFFICE Refiled for abandoned application Serial No. 61,001, January 27, 1936. This application May 15, 1937, Serial No. 142,88!

4 Claims.

The present invention relates to fuse devices, and has for its purpose the provision of a compact construction, of an efficient and inexpensive character, adapted to facilitate removal of the 5 fuse or the replacement of burnt-out fuses in a convenient and safe manner.

To this end I provide a fuse blockand receptacle therefor which is of a shock-proof character, and also adapted to obviate any danger of 10 explosions due to gases collecting within the space occupied by the fuse.

The invention further comprises a locking constructionto prevent unauthorized tampering with the device, which locking means involves a self- 15 locking feature and also includes a frangible element required to be broken for unlocking the fuse. Provision is also made for permitting the use of other locking means (such as the wire and seal type) if desired.

20 With the foregoing general objects in view, the invention will now be described by reference to the accompanying drawing illustrating suitable forms of embodiment of my improvements, after which those features deemed to be novel and 25 patentable will be particularly set forth and claimed.

In the drawing- Figure l is a front elevation showing a fuse device constructed in accordance with my inven- 30 tion;

Figure 2 is a vertical sectional view thereof, on a larger scale;

Figure 3 is a front elevation of the main receptacle, with the fuse-carrying block removed;

35 Figure 4 is a transverse section, representing a section taken on the line l4 of Figure 3;

Figure 5 is a side elevation of the fuse-carrying block;

Figure 6 is a rear face view of the same;

40 Figures 7 and 7a are sectional views of modified forms of the fuse-carrying block;

Figure 8 is a sectional view, representing a section taken on the line 8-8 of Figure 7; and

Figure 9 is a detail view of the detent or looking 46 device.

This application is a substitute application filed in lieu of an earlier application Serial #6l,00l which was filed January 27, 1936.

Referring now to the drawing in detail, the con- 50 struction illustrated comprises a receptacle member l and a fuse-carrying block I I of suitable non-conducting material such as glass or porcelain, and of such form that the receptacle substantially encloses or houses the sides and rear 55 or fuse-carrying face of the block I I, as shown in Figures 1, 2 and 4. The receptacle is provided with openings I! for screws H for attaching the receptacle in suitable position upon the face of a wall member I5, and also openings 16 for the circult or line wires H, for which appropriate terminal clips l8 are secured, as by screws 20, within the receptacle and equipped with binding screws 2| for securing the inner ends of the wires ii.

The space occupied by the clips I8 is closed over by a plate 24 of suitable non-conducting material which is secured in position by screws 26 and also formed with slots 28 for passage of the fuse terminals or contact elements 38 which are fastened by screws 32 within a recess 33 that are formed on the rear or inner face of the block i I. Fitting within this recess is also a cover plate 34 of suitable non-conducting material having slots 38 for passage of said terminals 30, which are connected by a suitable fuse element, such as a fusible link 38 as shown in Figures 2 and 6. Preferably the plate 34 is so formed as to project within the recess sufliciently to substantially fill and seal the remaining space therein, thus excluding gases from collecting around the fuse elements to any material extent.

In some instances it may be preferred to use a cartridge type of fuse, such as illustrated at 38' in Figures 7 and 8, in which case the contact elements of the fuse-carrying member H may be formed with clip portions ill for detachable engagement with such fuse-cartridge 38'.

In Figure 7a, the same form of fuse link 38", as shown at 38 in Figure 6, is illustrated as provided with spring clip mountings 3i in place of the securing screws 32, for quick replacement purposes.

It will be noted that on insertion of the fuse block H (which has a suitable handle portion 9) into the receptacle, the terminals 30 are projected through the slots 28 into enghgement with the 40 clips 13, and the slots 28 are of sumcient extent to permit upward sliding movement of said terminals, which are of L-shape as illustrated in Figures 2, 5 and 7, so that the shoulders at the angular portions of the terminals will effect retaining engagement at the ends of the slots (Figure 2).

While suitable openings 40, as shown in Figure 2, for the use of wire and seals may be provided for locking the parts in the relation shown in Figure 2, I illustrate an alternative form of looking means comprising a detent plate 42 adapted to be inserted in a recess 43 in one end of the fuse block II for engagement by a gravity dog 44 pivoted at 85 at the inner end of said recess. The

, condition of the fuse element, although this is plate is inserted into the recess 43, as illustrated in Figure 9, before the fuse block is placed into the receptacle, the gravity dog 44 being swung backward so that, after the parts are assembled in the relation shown in Figure 2, the plate drops into engagement with the interior wall of the receptacle l0 and is thus automatically locked by the dog 44 also swinging down into position to prevent any upward sliding of the plate. Preferably 'the detent plate 42, which is of suitable frangible material, is formed with a weakened line 42' whereby it may be broken by means of an appropriate tool when necessary to unlock and remove the fuse block. A suitable supply of the detent plates 42 may be furnished, bearing the power companys insignia to guard against unauthorized tampering with the construction, which would be evidenced by the use of a different form of these plates.

It will be apparent that the foregoing construction is of a type adapted to fulfill the various objects of my invention. The construction is safe and shockproof by virtue of the fact that there are never any exposed connections or contacts, either when the fuse block is in place or when it is removed. The construction is furthermore of a theft-proof character, due to there being no exposed connections, when the device is locked, which would permit connecting across the line terminals. Again, the improved construction is of particular value in buildings having numerous tenants for whom the current is metered separately, since by the improved device the service may be started or discontinued by simply installing or removing the fuse, and in either case leaving the device locked; this eliminates the time and expense of linemens operations at the poles or outside connections, and also the necessity of making breaks in the line from time to time which often results in uneven current supply and loss of power due to corrosion in defective connections.

The improved construction provides a compact appliance of a simple and economical type, in

which the operation of locking and unlocking the same for inserting or removing fuses is also simple and convenient. Obviously a suitable aperture or window could be included to show the not essential since the material of the fuse block may be sufficiently transparent (such as glass) to answer this purpose.

While I have shown and described what I now regard as the preferred form and mode of practicing my invention I desire to be understood as reserving the right to make such changes as may fairly fall within the scope of the appended claims.

What I claim is:

1. In a safety type fuse assembly, a receptacle provided with line contact terminals, an apertured shield plate forming a protective closure over said terminals, a removable fuse-carrying block mounted for slight longitudinal shifting movement within the receptacle and provided with fuse-contact terminals insertable through the apertures of said plates and movable with said longitudinal movement of the block for effecting engagement with said,1ine terminals, and automatically acting detent means operating to secure said block within said receptacle.

2. In a safety type fuse assembly, a receptacle provided with line contact terminals, an apertured shield plate forming a protective closure over said terminals, a removable fuse-carrying block adapted to be received within the receptacle and provided with L-shaped fuse-contact terminals insertable through the apertures of said plate into engagement with said line terminals and into hooked retaining engagement with said plate, and a detent device acting to prevent movement of the block for disengagement of said fuse terminals from the plate.

3. In a safety type fuse assembly, a receptacle provided with line contact terminals, an apertured shield plate forming -a protective closure over said terminals, a removable fuse-carrying block adapted to be received within the receptacle and'provided with L-shaped fuse-contact terminals insertable through the apertures of said plate into engagement with said line terminals and into hooked retaining engagement with said plate, and a frangible detent element slidably mounted in said block for engagement with the receptacle and preventing movement of the block for disengagement of said fuse terminals.

4. In a safety type fuse assembly, a receptacle provided with line contact terminals, an apertured shield plate forming a protective closure over said terminals, a removable fuse-carrying block adapted to be received within the receptacle and provided with L-shaped fuse contact terminals insertable through the apertures of said plate into engagement with said line terminals and into hooked retaining engagement with said plate, a sliding detent element carried by said block for engagement with the receptacle and preventing movement of the block for disengagement of said fuse terminals, and a gravity dog pivoted adjacent to said detent and operating automatically to hold the latter in locked position. 

